In a recent airline incident, a passenger boarded and plopped into his assigned seat. Moments later he discovered he had sat on a stinky souvenir left behind by a dog. Until recently, the only uncaged animals allowed on flights were registered service dogs.

However, a new category was created for so-called emotional support animals to occupy airline seats with their emotionally (and often mentally) needy owners. To do it legally, all it takes is a certificate from a doctor or registration with the airline, whether the animal is canine, feline, feathered or whatever.

So, in future flights, before you settle down into your seat, be sure to check first whether it’s clean or the previous non-human occupant left behind a rancid reminder.